package com.justnow.offer;

import java.util.Scanner;

/**
 * @author justnow
 * Created on 2020-09-19
 * Description
 */
public class JXJR02 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        String[] s = str.split(" ");
        String s1 = s[0];
        String s2 = s[1];
        String s3 = s[2];
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < 3; i++) {
            stringBuilder.append(s1.charAt(i));
            stringBuilder.append(s2.charAt(i));
            stringBuilder.append(s3.charAt(i));
        }
        System.out.println(stringBuilder.toString());
    }
}
